From eea15c3e4c2069d9f153c340e86f3f4e986a4223 Mon Sep 17 00:00:00 2001 From: cliven Date: Sat, 13 Aug 2022 15:18:47 +0800 Subject: [PATCH] =?UTF-8?q?SM2=E5=AF=86=E9=92=A5=E4=BA=A4=E6=8D=A2?= =?UTF-8?q?=E7=AE=97=E6=B3=95=E6=94=AF=E6=8C=81=E4=BA=86=E5=88=9D=E5=A7=8B?= =?UTF-8?q?=E5=8C=96=E6=97=B6=E6=B2=A1=E6=9C=89=E5=AF=B9=E7=AB=AF=E5=85=AC?= =?UTF-8?q?=E5=BC=80=E4=BF=A1=E6=81=AF=EF=BC=8C=E5=9C=A8=E5=90=8E=E7=BB=AD?= =?UTF-8?q?=E5=8A=A0=E5=85=A5=E5=85=AC=E5=BC=80=E4=BF=A1=E6=81=AF=E7=9A=84?= =?UTF-8?q?=E6=96=B9=E6=B3=95=E3=80=82?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- sm2/sm2_keyexchange.go | 43 ++++++++++++++++++++++++++++--- sm2/sm2_keyexchange_test.go | 50 +++++++++++++++++++++++++++++++++++++ 2 files changed, 89 insertions(+), 4 deletions(-) diff --git a/sm2/sm2_keyexchange.go b/sm2/sm2_keyexchange.go index c980349..5975c54 100644 --- a/sm2/sm2_keyexchange.go +++ b/sm2/sm2_keyexchange.go @@ -35,10 +35,14 @@ func (ke *KeyExchange) GetSharedKey() []byte { } // NewKeyExchange create one new KeyExchange object +// +// 在部分场景中，在初始 KeyExchange 时暂时没有对端的公开信息（如公钥、UID），这些信息可能需要在后续的交换中得到。 +// 这种情况下，可设置 peerPub、peerUID 参数为 nil，并在合适的时候通过 KeyExchange.SetPeerPub 方法配置相关参数。 +// 注意 KeyExchange.SetPeerPub 方法必须要在 KeyExchange.RepondKeyExchange 或 KeyExchange.RepondKeyExchange 方法调用。 func NewKeyExchange(priv *PrivateKey, peerPub *ecdsa.PublicKey, uid, peerUID []byte, keyLen int, genSignature bool) (ke *KeyExchange, err error) { ke = &KeyExchange{} ke.genSignature = genSignature - ke.peerPub = peerPub + ke.keyLength = keyLen ke.privateKey = priv w := (priv.Params().N.BitLen()+1)/2 - 1 @@ -48,24 +52,49 @@ func NewKeyExchange(priv *PrivateKey, peerPub *ecdsa.PublicKey, uid, peerUID []b x2minus1 := (&big.Int{}).Sub(x2, big.NewInt(1)) ke.w2Minus1 = x2minus1 + if len(uid) == 0 { + uid = defaultUID + } ke.z, err = calculateZA(&ke.privateKey.PublicKey, uid) if err != nil { return nil, err } - ke.peerZ, err = calculateZA(ke.peerPub, peerUID) + + err = ke.SetPeerPub(peerPub, peerUID) if err != nil { return nil, err } + ke.secret = &ecdsa.PublicKey{} ke.secret.Curve = priv.PublicKey.Curve - ke.peerSecret = &ecdsa.PublicKey{} - ke.peerSecret.Curve = peerPub.Curve + ke.v = &ecdsa.PublicKey{} ke.v.Curve = priv.PublicKey.Curve return } +// SetPeerPub 设置对端公开信息，该方法用于某些初期状态无法取得对端公开参数的场景。 +// 例如：在TLCP协议中，基于SM2算法ECDHE过程。 +func (ke *KeyExchange) SetPeerPub(peerPub *ecdsa.PublicKey, peerUID []byte) error { + if peerPub == nil { + return nil + } + if len(peerUID) == 0 { + peerUID = defaultUID + } + + var err error + ke.peerPub = peerPub + ke.peerZ, err = calculateZA(ke.peerPub, peerUID) + if err != nil { + return err + } + ke.peerSecret = &ecdsa.PublicKey{} + ke.peerSecret.Curve = peerPub.Curve + return nil +} + func initKeyExchange(ke *KeyExchange, r *big.Int) { ke.secret.X, ke.secret.Y = ke.privateKey.ScalarBaseMult(r.Bytes()) ke.r = r @@ -154,6 +183,9 @@ func respondKeyExchange(ke *KeyExchange, r *big.Int, rA *ecdsa.PublicKey) (*ecds // RepondKeyExchange when responder receive rA, for responder's step B1-B8 func (ke *KeyExchange) RepondKeyExchange(rand io.Reader, rA *ecdsa.PublicKey) (*ecdsa.PublicKey, []byte, error) { + if ke.peerPub == nil { + return nil, nil, errors.New("sm2: peer public not set, you probable need call KeyExchange.SetPeerPub") + } if !ke.privateKey.IsOnCurve(rA.X, rA.Y) { return nil, nil, errors.New("sm2: received invalid random from initiator") } @@ -167,6 +199,9 @@ func (ke *KeyExchange) RepondKeyExchange(rand io.Reader, rA *ecdsa.PublicKey) (* // ConfirmResponder for initiator's step A4-A10 func (ke *KeyExchange) ConfirmResponder(rB *ecdsa.PublicKey, sB []byte) ([]byte, error) { + if ke.peerPub == nil { + return nil, errors.New("sm2: peer public not set, you probable need call KeyExchange.SetPeerPub") + } if !ke.privateKey.IsOnCurve(rB.X, rB.Y) { return nil, errors.New("sm2: received invalid random from responder") } diff --git a/sm2/sm2_keyexchange_test.go b/sm2/sm2_keyexchange_test.go index bf14989..f4f4cf7 100644 --- a/sm2/sm2_keyexchange_test.go +++ b/sm2/sm2_keyexchange_test.go @@ -41,3 +41,53 @@ func TestKeyExchangeSample(t *testing.T) { t.Errorf("got different key") } } + +func TestKeyExchangeNoPeerPubInit(t *testing.T) { + priv1, _ := GenerateKey(rand.Reader) + priv2, _ := GenerateKey(rand.Reader) + uidA := []byte("Alice") + uidB := []byte("Bob") + + initiator, err := NewKeyExchange(priv1, nil, uidA, uidB, 32, true) + if err != nil { + t.Fatal(err) + } + responder, err := NewKeyExchange(priv2, nil, uidB, uidA, 32, true) + if err != nil { + t.Fatal(err) + } + + rA, err := initiator.InitKeyExchange(rand.Reader) + if err != nil { + t.Fatal(err) + } + + // 设置对端参数 + err = initiator.SetPeerPub(&priv2.PublicKey, uidB) + if err != nil { + t.Fatal(err) + } + err = responder.SetPeerPub(&priv1.PublicKey, uidA) + if err != nil { + t.Fatal(err) + } + + rB, s2, err := responder.RepondKeyExchange(rand.Reader, rA) + if err != nil { + t.Fatal(err) + } + + s1, err := initiator.ConfirmResponder(rB, s2) + if err != nil { + t.Fatal(err) + } + + err = responder.ConfirmInitiator(s1) + if err != nil { + t.Fatal(err) + } + + if hex.EncodeToString(initiator.key) != hex.EncodeToString(responder.key) { + t.Errorf("got different key") + } +}